Integrated Pest Management for Raspberries

A Guide to Sampling and Decision Making for Key Raspberry Pests in Northwest Washington

Dan Coyne • Geoff Menzies • Colleen Burrows • Craig MacConnell

 

Introduction

This manual is intended to be used as a tool to aid in sampling and decision-making for managing key insect, mite, and disease pests in Northwest Washington raspberry fields. It compiles information from numerous written sources and practical pest scouting experience of growers in Whatcom County.

The manual is organized based on crop stage and pest development because this is the way the grower or scout encounters raspberry pests and decides how to manage them.

 

The crop stages are divided into four periods:

Key pest biology, sampling methods, and treatment thresholds are presented in a narrative form and in a table or matrix form for each of these four crop stages. In addition, a proposed sampling form (permanent record of each field visit) can be found at the end of each crop stage section. Pest profiles are provided for each insect, disease, and weed pest – these sheets provide information on the identification, life history, and management of the pest as well as pictures and links to other relevant web pages. The manual is designed so that components such as the matrix or record-keeping forms can be taken out and copied or hung on the wall for easy reference. Other sections of the manual include an IPM Sources List (publications, suppliers of scouting and weather monitoring equipment), Tables and Figures (pesticide selection, pest development graphs), and Key Insect and Disease Identification Sheets, Beneficial Insects and Pesticides and Water.

It is our hope that growers, chemical company field representatives, private consultants, extension agents, and others who are interested in raspberry IPM will use this manual. This manual has been designed in an online format, which will allow the user to easily navigate through the manual and print pages where required. New information will be added to the web version as it is developed. The development of IPM in blueberries, as in other crops, will continue to change and improve; it is a dynamic process affected by many factors. The design of this manual reflects the evolving field of Integrated Pest Management.

Rationale

Regular field scouting for key pests is an important component of any IPM Program. Raspberry growers rely primarily on themselves, chemical company field representatives, and hired consultants to help them scout and make pest management decisions. The methods, intensity, and frequency of sampling vary considerably among these groups. IPM scouting is both time and knowledge-intensive. Scouting methods must be well-focused, relatively simple, and still designed to produce information that is meaningful and useful to the grower. The scouting methods discussed in this manual were field-tested by three raspberry growers during the 1997 summer season. Experience with these growers as well as their comments has helped to shape this manual. When it comes to decision-making in raspberry pest management, there is strength in numbers. Growers have an active role to play in gaining a better understanding of raspberry pests in their fields, and by performing some of the basic scouting and record-keeping procedures outlined in this manual, they can be more informed and more involved in pest management decision-making.

Pest Scouting in Raspberry Fields

Regular systematic scouting and recordkeeping is the fundamental component of Integrated Pest Management. The scouting season typically begins in late March or early April with an assessment of cutworm damage to developing buds and ends in early September with nematode sampling. Eight to ten well-timed trips through the field for the entire season are usually enough to provide valuable information on which to base decisions. Experience with the Nooksack IPM program shows that scouting and recordkeeping take about an hour for each field visit. This represents a total, season-long investment of eight to ten hours per field. The important thing is to be systematic and use your time efficiently, concentrating on the key pests and tasks at hand.

Scouting path for raspberries

Scouting involves performing usually two or three tasks at each of three to five sites in a field. A minimum of three sites should be checked in small fields (<10 acres) and five sites are usually adequate in larger fields (20 acres or more). Sampling in several sites rather than just in a spot or two will illustrate the range of variation of pest abundance found across a field. Recording information on a site by site basis allows the sampler to return at a later time to determine trends in pest population which are helpful in making decisions and evaluating treatments that have been applied. Use existing knowledge about the field’s history or variations that exist within a field to determine sampling site locations. In general, sites should be distributed throughout a field and the scout should return to those approximate areas for each visit. The manual describes scouting procedures that should be conducted at each site during each crop stage.

Fields should be checked on approximate two-week intervals from late March through late June (six to seven visits) prior to the onset of harvest. Sampling during harvest is difficult due to time constraints but careful observations of insects that may be present on the harvesting belt are a form of scouting as well. Fields should be checked on approximate two-week intervals starting immediately after harvest and into early September (two to three visits). The graph at the end of this section illustrates important sampling periods based on crop stage and an approximate date for key insect, disease, and nematode pests.

Scouting Equipment

Magnifying Hand Lens (10X power) or an OptiVisor (3.5X power)

 

Small Notebook (3″ X 5″) or a Clipboard with Report Form Attached

 

Beating Tray

 

Carpenter’s Apron or Nail Pouch

The tools used in scouting are quite simple. For most of the field visits, you should have the following equipment with you when you enter the field:

For it to be convenient, a hand lens should be tied to a small nylon line (loop) and hung from the neck so it frees up the hands and is accessible when needed. It is used most often for identifying and counting mites and their predators in the field. Some growers prefer using an Optivisor, usually of lower but adequate magnification. These fit around the head with an adjustable headband and have a flip-down lens, so both hands are free to hold and examine the object.

The notebook is used to record data and observations from each site that is visited in the field. Site numbers are usually written across the top of the page and pests that are being monitored are listed in a column on the left side of the page. Refer to the Report Forms for each crop stage to create this temporary form in the small notebook. Some may find it more convenient to use a clipboard and fill out the full-sized (8 1/2 X 11) report in the field rather than copying data from the small notebook into the final report.

An 18″ X 18″ canvas or cloth-covered tray is very useful for sampling numerous beneficial and pest insects that reside in the canopy. A tray designed by the Nooksack IPM Project has a frame and handle built of 1/2″ PVC pipe and a black and white-sided cover made of a locally available material called “Sunbrella” (see drawing in IPM Source List section). The material cost for this tray is about $25. Similar trays can be constructed with other locally available materials as well.

Particularly when walking a field to scout, a carpenter’s apron provides additional pockets for holding a small notebook, penknife or pruning shears, pencil, and small containers such as an empty film canister or plastic bag for collecting insect specimens or foliage.